Without limiting the scope of the invention, its background is described in connection with compositions that mimic peptides and proteins, methods of making the compositions and using the compositions in the treatment of diseases. Diabetes mellitus, and associated complications, is the third leading cause of death in the United States and one of the most widespread degenerative diseases. Generally, diabetes mellitus affects the conversion of sugars and starches into glucose during digestion. A pancreatic hormone, insulin, plays a key role in the storage and use of carbohydrates, protein and fat as a source of energy for the body. Insulin deficiency is a common and serious pathologic condition, which may lead to blindness, kidney failure and limb amputations.
Diabetes is a chronic disease characterized by multiple metabolic abnormalities resulting in impaired management of glucose. Generally, diabetes can be classified into insulin-dependent diabetes mellitus (Type I) and non-insulin-dependent diabetes mellitus (Type II). Insulin-dependent diabetes mellitus (Type I) is characterized by the production of little or no insulin by the pancreas and requires daily insulin injections for treatment. Non-insulin-dependent diabetes mellitus (Type II) is characterized by a combination of reduced insulin responsiveness and a relative deficiency of insulin production. The most common form of diabetes is Type II, which affects about 90-95% of diabetic patients.1,2 The treatment of non-insulin-dependent diabetes mellitus (Type II) is more challenging due to the complex pathogenesis involving progressive development of insulin resistance and deficiency in insulin secretion.4 
The major pancreatic islet hormones, glucagon, insulin and somatostatin, interact with and/or originate from specific pancreatic cell types to modulate the secretory response. Glucagon is derived from the processing of proglucagon, which is in itself derived from the 360 base pair preproglucagon gene. However, proglucagon also contains two other discrete and highly homologous peptide regions designated glucagon, glucagon-like peptide-1 (GLP-1) and glucagon-like peptide-2 (GLP-2). The 30-amino acid glucagon-like peptide-1 (GLP-1) has been shown to function as a stimulus of insulin secretion.
GLP-114 is produced by intestinal L-cells through the proteolytical processing of preproglucagon.5-8 GLP-1 functions by acting on a cognate peptide receptor (GLP-1R). In addition to enhancing insulin secretion and restoring glucose sensitivity to the islets, this peptide also increases expression of the glucose transporter and glucokinase.14-16 
Additionally, GLP-1 displays numerous beneficial effects on regulating β-cell mass by stimulating replication and growth of existing β-cells, inhibiting apoptosis, and triggering neogenesis of new β-cells from duct precursor cells.17,18 GLP-1 also inhibits secretion of glucagon which is often found in abnormally high concentrations in diabetic patients.19,20 Apart from these effects, it is a potent inhibitor of gastric emptying,21 and causes an inhibition of appetite with suppression of food intake. This results in a decrease in body weight, making GLP-1 an efficient treatment of obesity which often accompanies diabetes.22,23 Since all these GLP-1 induced functions are extremely favorable to the treatment of Type II diabetes, therapies based on this peptide hold considerable clinical promise.24 
For example, one method for regulation of glucose and lipid metabolism, generally to reduce hyperglycemia, insulin resistance, obesity, hyperlipidemia, and hyperlipoproteinemia, is taught in U.S. Pat. No. 7,157,429 issued to Bachovchin, et al. entitled Method of regulating glucose metabolism and reagents related thereto. It includes dipeptidylpeptidase inhibitors, which are able to inhibit the proteolysis of GLP-1 and accordingly increase the plasma half-life of that hormone. The subject inhibitors may be peptidyl, peptidomimetic (e.g. boronyl peptidomimetics), or non-peptidyl nitrogen containing heterocycles.
Conventional methods for identifying such inhibitors include the preparation and screening of chemical libraries to discover lead compounds although often with little success.